Retaining means for rubber linings



Oct. 20, 1936. J. A. PoRTEous RETAINING MEANS FOR RUBBER'LININGS FiledApril 27, 1955 ATTORNEY.

' Patented Oct. 20, 1936 UNITED STATE s PATENT OFFICE John A. Porteous,Montreal, Quebec, Canada, as-

signor to United States Rubber Products, Inc., New York, N. Y., acorporation of Delaware Application Apr-i127, 1935, Serial No. 18,534

' 1 Claim. (o1: 83- 9 My invention relates to retaining means for rubberlinings, and more particularly to means for securing rubber linings tometal shells.

-A rotary mill for mixing and/or pulverizing varioustypes of materialsin'common use is characterized by a shell, at least part of which iscylindrical, having a rubber lining which protects the metal of theshell against the action of chemicals destructive to metal; and alsoagainst the wearing action of the material placed therein and metalballs, and ,the like which are sometimes added for pulverizing ores andother lumpy materials. The ends of the shell are closed by plates havingrubber faces which plates may be provided with suitable ports or otheropenings for feeding or dischargingmaterials. As the linings of suchmills must be replaced from time to time, it is preferable that therubber detachably secured to the shells.

The detachable securing of such rubber linings to the metal shells hashereinbefore involved much diflic'iflty. A common method for securinsuch linings has been to place iron bars extending longitudinally of theshell over the rubber at suitable intervals, and secure themby boltsextending through the bars, the underlying rubber and the shell. As theexposed metal bars wear shallbe a metal shell 2 constituting the body orcylindrical portion of a mixing or pulverizing mill. However, it is tobe understood that the invention is applicable to other shapes ofshells. The shell 2 is provided with flanges 3having bolt holes 4 forthe attachment of the end plates, not shown. Ordinarily, the cylinderand/or the end plates are provided with means for rotating the mill, butwhich are not shown in the drawing as they form nomaterlal part of thepresent invention. The shell is provided with lining strips or sections5 of rubber, usually soft rubber, although semi-hard rubber compositionsmay be used for some purposes, as'is well known in the art. The strips 5are provided with shouldered edges 6 for the reception of retaining orsecuring bars I. The

strips 5 and the bars 1 collectively form a confaster than the rubberthere is a tendencyfor the bars to wear out before the rubber. In orderto avoid frequent replacement of the bars, there is a tendency to usevery thick bars which causes them to initially extend well above theface of the rubber and to be subjected to excessive wear as well asproducing an excessively uneven surface in the mill. Even then therubber lining usually outlasts the life of several sets of bars.

By the present invention I provide for detachably retaining such rubberlinings by utilizing bars entirely covered with rubber of substantiallythe same thicknesses the thickness of the rubber lining, therebypresenting .a rubber surface of uniform thickness to the material in themill whereby the lives of the retaining bars are substantially the sameas the life of the lining.

The accompanying drawing illustrates a present preferred embodiment ofthe invention, in which:.

Fig. l is a perspective view of a cylindrical portion of a mixing orpulverizing millwith the lining in place, the end pieces being removed:

Fig. 2 is a transverse sectional view of a portion of the mill takenalong the section line indicated by reference numerals 3-11; and

Fig. 3- is aperspective view of a retaining bar. Referring to thedrawing, there is illustrated tinuous rubber lining around the inside ofthe shell.

Referring particularly-to Figs. '2 and 3, each retaining bar 1 comprisesa metallic core 8 of approximately the width of each of the recesses 6.The metal bar 8 is preferably thicker near its centre than at itsedges'to fill the spaces between the edges of the strips 5' and engagethe inner surface of the shell.

In manufacturing the bars 1, the metal bars 8 are first covered with alayer of rubber-to-metal adhesive ill for securing a layer ll of rubber.The rubber layer II is in turn .covered with a wrapping 12 of fabric,preferably duck. The bar so formed is placed in a mold with a batch of?rubber engaging the fabric on the outer or smooth face of the bar. Uponvulcanizing the outer or surface rubber I4 is: bonded directly to theduck layer. The layer It terminates at the edges of the bar 8 so thatthe fabric l2 on the other face may directly engage the bottom of arecess 6. The rubber layer M is made of substantially the same thicknessas the strips 5.

The outer surface of the rubber layer It is curved so that when, thecompleted retaining bar I is mounted in the shell, as shown in Fig. 2,the interior of the mill presents a continuous rubber surface of uniformdepth of active cushion-- in rubber, although the surface is providedwith. irregularities or waves which are-of some advantage in theoperation of the mill. 'Each retaining bar I fills the recess in whichit is seated, and

by extending the bolts 9 through the outer' shell, 50 they may besecured by nuts IS without exposing the strips 5, give substantiallyuniform wear for both the bars and the lining so that one set of tion01' one face for cooperation with a mill wall retaining bars I will lastfor substantially the toprovide spacesior clamping lining'edgea, Wu lifeof the strip 5. ing means for the bar on the raised portioncon- While Ihave shown and described a present nected to the mill wall, a lining forthe mill wall 5 preferred embodiment of my invention, it is to be havingedges secured between the bar and mill 5 understood that various changesmay be made wall and having-spaced inwardly extendingportherein withoutdeparting from the spirit '0! the tions, and a rubber layer securedtoethe bar opinvention and the scope of the appended claim. posite theraised portion, said rubber layer being Having thus-described 'myinvention, what I of substantially the same thickness as said por- 10claim and desire to protect by LettersPatent is:-- tlons and havingoutwardly flaring edges to pro-' 1 In combination, a retaining bar for amill linvide a beveled flt therewith. ing comprising a. metal bar havinga raised por- JOHN A. PORTEOUS.

